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By C E. Vidal

Geological exploration and mining development increased their intensity and rate of success during the last five years in Peru. Particularly relevant are the mining projects of Yanacocha and Pierina for epithermal Au and Ag. Also relevant are the new mining operations at Iscaycruz and Uchucchacua for limestone replacement Zn- or Ag-rich base metal skarn deposits. Miocene continental volcanics host the low-grade but near-surface orebodies of the Yanacocha mining district in Cajamarca. Several deposits have been mined since 1994 with open-pit and heap-leach gold production increasing from 300 000 ounces to 1 300 000 ounces in 1998. In a similar geological setting, but with three times the grade of Yanacocha, the Pierina valley-leach operation in Ancash is set to produce 800 000 ounces Au during 1999. At Iscaycruz in Lima, Cretaceous limestones host massive pyrite and sphalerite skarn deposits with 10 to 20 per cent Zn. Mining and milling were started in 1996 with last yearÆs production rising to 180 000 tonnes of Zn concentrates. At Uchucchacua, selective underground mining of fracture-controlled Ag skarns, with 400 to 420 g/t, has been recently increased from 1200 to 2000 tonnes per day to produce 5.5 million ounces Ag during 1998. Advanced exploration projects are located in the framework of nine Phanerozoic metallogenic provinces. Mineral deposits of preferred attention are precious metal disseminations and veins, base metal replacements and skarns, porphyry Cu (Mo-Au), Mississippi-Valley-type Zn and base metal volcanogenic massive sulphide deposits. Geological discovery of new orebodies enables a sustainable development of the mining industry in the country.

Jan 1, 1999

By H W. Wu, D Humphreys

The structure of a comprehensive research project into mine fires study applying the Ventgraph mine fire simulation software, preplanning of escape scenarios and general interaction with rescue responses is outlined. The project has Australian Coal Association Research Program (ACARP) funding and also relies on substantial mining company site support. This practical input from mine operators is essential and allows the approach to be introduced in the most creditable way. The effort is built around the introduction of fire simulation computer software to the Australian mining industry and the consequent modelling of fire scenarios in selected different mine layouts. Application of the simulation software package to the changing mine layouts requires experience to achieve realistic outcomes. Most Australian mines of size currently use a ventilation network simulation program. Under the project a small subroutine has been written to transfer the input data from the existing mine ventilation network simulation program to æVentgraphÆ. This has been tested successfully. To understand fire simulation behaviour on the mine ventilation system, it is necessary to understood the possible effects of mine fires on various mine ventilation systems correctly first. Case studies demonstrating the possible effects of fires on some typical Australian coal mine ventilation circuits have been examined. The situation in which there is some gas make at the face and effects with fire have also been developed to emphasise how unstable and dangerous situations may arise. The primary objective of the part of the study described in this paper is to use mine fire simulation software to gain better understanding of how spontaneous combustion initiated fires can interact with the complex ventilation behaviour underground during a substantial fire. It focuses on the simulation of spontaneous combustion sourced heatings that develop into open fires. Further, it examines ventilation behaviour effects of spontaneous combustion initiated pillar fires and examines the difficulties these can be present if a ventilation reversal occurs. It also briefly examines simulation of use of the inertisation to assist in mine recovery. Mine fires are recognised across the world as a major hazard issue. New approaches allowing improvement in understanding their consequences have been developed as an aid in handling this complex area.

Jan 1, 2005

Who Macraes Mining Company Limited is can be summed up by the following statements: +         We have been New Zealand's largest gold producer for seven years +         We have one of the lowest market capitalisation per reserve ounce of the gold producers in the  Australian Gold Index +         We have a resource finding cost of less than NZ$l0 per ounce +         We have a large land bank with proven reserves +         We have an Operating Cash Margin of approximately NZ$200 per ounce +         We have reduced our Dry Milled Tonne Cost by 34% since 1992   Our Mission is to continually grow our gold business, through maximising cashflow and focusing on our value drivers being: +         Increasing reserves +         Increasing cash operating margins +         Increasing production   The real challenge is the reduction of operating costs and the optimisation of revenue, particularly in the current gold price environment.   The Company has as at 31 December 1996 total mineral resources of 6.1 million ounces and reserves of 3.4 million ounces. This together with our current cash position of approximately NZ$15 million and strong hedging book of approximately 800,000 ounces places the Company on a sound financial footing whilst positioning itself to aggressively pursue its growth strategy when gold price and market conditions improve.

Jan 1, 1997

Underground mine planning is characterised by a series of designs, starting with prefeasibility and culminating in operational. Information on the mineralisation and geotechnical conditions is available in increasing levels of detail, as development occurs. In the recently completed AMIRA Planning and Rapid Integrated Mine Optimisation (PRIMO) project, a methodology for producing good strategic and then tactical designs using new optimisation tools, was developed. At the strategic level, fundamental decisions must be made such as those relating to cut-off grade, bench heights, mining methods, access and haulage systems, properties of the mill, etc. The inputs are the block and financial models, geotechnical data, infrastructure and production costs, etc. Stope definition for strategic designs includes bench RLs (relative levels), orebody envelopes, and design and placement of amalgamated or simplified stopes. If multiple mining methods are under consideration, then stopes need to be associated with these. Access design must take into account decisions such as declines versus shafts, a template for level layouts and the topology of the access network. Some of the geotechnical and physical constraints are relaxed for strategic design stages. Strategic scheduling is high level, from a month to a year at a time. In the PRIMO project, software tools have been developed enabling the mine planner to rapidly produce a large number of such strategic designs. After the designs have been evaluated, the highest value designs are chosen and a small number of these can then be further refined at a tactical level. For these designs, the first step is determination of all stopes meeting physical and geotechnical requirements and constraints, allowing for complex stope shapes. Next, detailed layout of the mine access network is obtained, satisfying all operational and geotechnical constraints. Finally, more detailed scheduling is performed, over shorter time periods. The Melbourne University group has focused on optimal access design. In particular, the access network is optimised for minimum cost, taking into account the cost of haulage and development over the lifetime of the mine. Costs vary over the different parts of the network depending on the quantity of haulage and so a weighted network optimisation problem has to be solved. We have developed two software tools for this task, decline optimisation tool (DOT) and planar underground network optimiser (PUNO). DOT produces an optimal network of declines and crosscuts connecting access points on the levels to a portal or break-out point from existing infrastructure. PUNO designs the level layout, including footwall and hanging wall drives, development drives and connections to vent raises. A survey will be given of the capabilities of DOT and PUNO when used on some recent case studies. Our current goals include incorporating some aspects of ventilation design and modelling the development costs when additional ground support is required. This is an abstract only. A full paper was not prepared for this abstract.

Dec 6, 2010

The New South Wales coal industry is a highly mechanised well organised industry which has developed from an annual production of slightly less than 13 million tons in 1950 to over 33 million tons in 1969. Although continuous miners were not introduced into the mines until 1950, by Jillle 1969 the percentage of coal won by these units was 87.3. The paper describes mining conditions in the various coalfields of the State, their complexities and problems and how these have been dealt with. The introduction of fully mechanised long wall faces has presented a challenge which has been accepted and descriptions of systems in use are discussed. Major expansion of the industry is anticipated to meet the requirements of the growing Australian steel industry, for local power generation and to meet the increasing demands of overseas markets.

Jan 1, 1971

By Taylor G. H

The Triassic Ipswich (SE. Queensland) coals are of bituminous rank. The more exact rank of individual samples was determined by measuring the reflectance of the vitrinite. While in general the rank of the coals increases with stratigraphic depth, minor reversals, probably related to igneous intrusions, occur.The Ipswich coals form a coherent group so far as petrographic type is concerned. All are comparatively rich in vitrite and clarite, cutinite being the common maceral of the exinite group. The mineral contents of all the coals are comparatively high, clay and quartz being most abundant. The coals appear to be of essentially autochthonous origin, and to have been formed under conditions of fairly rapid subsidence.While the use of the coals is at present restricted to combustion, most have pronounced coking properties, as would be predicted from their petrographic composition and reflectance. However, the high mineral content of the coals would be a limiting factor in their use for coke-making.INTRODUCTIONDuring the last ten years, the Division of Coal Research, Commonwealth Scientific and Industrial Research Organization has carried out an extensive investigation of Australian coals, providing a wide range of analyses of most of the important of them. Special attention has been given in recent years to Queensland coals.Most seams were sampled as a number of subsections, enabling the internal variations, as well as the overall properties, to be assessed. The lenticularity of many of the mineralrich layers may tend to limit the significance of the samples, particularly in respect of ash yield, but although the vertical distribution of mineral matter may vary considerably from one sampling position to another, the lateral variation of the total mineral matter in the whole seam may not be great.Apart from extensive chemical analyses and utilization...

Jan 1, 1963

By P González, J Videla, E Córdova, I Gottreux

Currently, underground mining of deeper massive deposits with lower grades, harder rock conditions in high strength environments, entails difficulties in caving, fragmentation and seismicity of the orebody.So far, the use of preconditioning (PC) with hydraulic fracturing (HF) has shown positive results in terms of seismic response and caving performance, while PC combined with explosives aims to weaken the rock mass, causing an additional effect on fragmentation.In particular, mines commonly referred to as ‘supercaves’, operated by caving methods, have the need to integrate mine to plant processes, where rock fragmentation appears as a key tool. In fact, it implies making mining and comminution processes more efficient to the plant and for mines, it justifies the search of innovative solutions in drilling and blasting techniques to precondition the rock mass. The following paper aims to show the feasibility of numerical blast modelling to weaken the rock mass using explosives, mainly through sensitivity analysis applied to designs to minimise bias and uncertainty in the results. It is shown how the presence of structures, their geometry and in situ stresses influence or interfere with the PC method being used.From the work, it is concluded that better knowledge on the application of explosives weakening allows specialists to strengthen numerical models associated with every design and therefore previously validate their applicability, helping to understand complex phenomena such as the propagation of mechanical waves in non-elastic heterogeneous media. In this sense, it is understood that while there are studies (Sanchidrián, Segarra and López, 2006) showing that the transfer of energy in the rock mass could be even greater in a confined environment, the more competent rock mass and higher in situ stresses interfere mostly on the effectiveness of a technique using explosives.CITATION:Gottreux, I, Córdova, E, González, P and Videla, J, 2016. Preconditioning modelling and explosives effectiveness in block caving, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 683–688 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By Parker A. J, Grimsey E. J

Studies have been carried out on the dead roasting of a copper-iron and a copper-nickel-iron sulfide concentrate, followed by segregation roasting with coal and leaching with either curpric sulfate in aqueous acetonitrile or cupric chloride in brine solution to preferentially solubilize copper. The effect of dead roasting and segregation roasting conditions on the overall leaching of copper and the separation of copper from iron and iron and nickel is reported. An excellent separation of copper from iron and a good separation of copper from iron and nickel can be obtained provided sulfur is removed to 0.5 per cent or less during the dead roast and provided the coal addition and temperature of the segregation roast are near the minima required for the segregation of copper.

Jan 1, 1983

The need for legislative reform of health and safety legislation has been recognised in New Zealand for about a decade. Previous legislation did not cover all work places, many areas were excluded from coverage, and there were at least 14 different acts and dozens of sets of regulations dealing with various aspects of health and safety.

Jan 1, 1993

Two types of low-sulphidation epithermal mineralisation may be recognised in volcanic terranes. Chalcedonic Silica- Adularia-Illite type mineralisation is most common in rhyolitic terranes, whereas Crystalline Quartz-Illite-(Adularia- Kaolinite) type mineralisation is more typically formed in andesitic terranes. A third type of epithermal mineralisation, the high sulphidation or Vuggy Silica-Alunite- Kaolinite-Illite type, is also common in andesitic terranes. Episodic violent boiling, accompanying hydraulic fracturing and hydrothermal eruptions, characteristic of geothermal systems in rhyolitic terranes, is stressed for the formation of Chalcedonic Silica mineralisation. Such boiling of deeply circulating meteoric groundwater, with some magmatic fluid contribution, provides chalcedonic veining, episodic banding and brecciation textures, adularia stability, bladed calcite, and extreme loss of H2S from the fluid to cause major gold deposition. Crystalline Quartz mineralisation is probably caused by the mixing of shallow acidic groundwater with ascending deep geothermal fluids beneath andesitic strato- volcanoes. The cooling effect, oxidation, and increased acidity, overcomes the dilution effect, and results in quartz deposition, illite (and locally kaolinite) alteration, and precipitation of metals. Extensive formation of base-metal sulphides further enhances gold deposition. Violent boiling is restricted to local structural dilation sites, potentially producing high grade "bonanza" gold mineralisation.

Jan 1, 1991

Using a cylindrical hydrocyclone with a long vortex finder as the separator, a batch sizer was developed for the fast comparative sizing of the coarse solids normally encountered in mineral pulps.Operating times as short as 2 or 3 min gave separations ranging from 16 mesh down to the subsieve sizes.Reproducibility was good and sensitivity was adequate for most applications.

Jan 1, 1968

By Creelman C. A

The removal of a horizontal piIlar between Nos. 9 and 11 levels (1,116 feet from the collar of main shaft) was successfully carried out by blast hole drilling, and, to the best of the authors' knowledge, this mass blast of 40,000 tons of ore (requiring the use of 7,150 Ibs. of explosive and 5,385 feet of primacord) was the first occasion on which a task of this magnitude has been carried out underground in an Australian mine.Blast hole drilling was introduced by this company approximately fifteen months ago at New Cobar Mine in sub-level stoping.This experimental drilling and blasting gave very valuable information as to the correct technique to be adopted when the final plans were being prepared for the removal of the horizontal pillar at New Occidental Mine.The dimensions of this pillar were approximately 15 feet long, and from 40 to 60 feet wide, and 65 feet in depth.The block of ore extended to 35 feet above the level and 30 feet below, the upper section being partially excavated to form the bell-hole floor and grizzly chambers used for drawing off the broken ore in the shrink stope above the No. 10 level.Description of Ore-bodyThe main ore-body is situated almost vertically in a well-defined shear zone at the junction of sandstone and slate, the sandstone forming the eastern and the slate the western wall.The ore-body consists of highly silicified slate (chert) sparsely impregnated with sulphides, containing a small percentage of copper and bismuth.The total length of the ore-body is approximately 450 feet, with a maximum width of 60 feet in the main section, which is about 200 feet long.This is the section shown in longitudinal and cross-section (Fig. 1).The ore-body is divided by a horse of mullock in the northern end into two legs, the eastern and western, which are approximately 250 feet long and averaging 25 feet in width.This ore-body is strong, hard and abrasive with extremely strong walls, an ideal proposition for open stoping and mass blasting.MiningIn all levels above No. 9 the cut and fill method of ore extraction was adopted. On Nos. 10 and 11 levels the shrinkage method was introduced with economical results, and no difficulty had ever been experienced with shabby or bad walls.Shrink stoping had been carried upwards from No. 11 level to within 10 feet of No. 10 level, when mining hazards developed, and instead of...

Jan 1, 1944

GENTLEMEN, lt is with much pleasure I meet you tonight at this the second meeting of the Australasian Institute of Mining Engineers, held in Western Australia, and I sincerely thank you for the honour you have conferred upon me in electing me as your President. I greatly appreciate the distinction, and will endeavour to fulfil the duties of the office to the best of my ability, and hope to prove a worthy successor to those gentlemen who have held the position before me. On behalf of the local members of the Institute, I extend a hearty welcome to the members from the other States of the Commonwealth, who have come so far to attend this meeting, and also to the non-members whom we have invited this evening. We are especially pleased to have Mr. Gregory, our Minister of Mines and Railways, and the Government and School of Mines officials with us; and I take this opportunity to thank the Premier, Mr. Gregory, and the Government officials for the assistance given us, and for doing so much to make the visit of our members from the other States so pleasant and instructive. I have also to thank the Mayor and Councillors of Kalgoorlie for the courtesy and hospitality given to our members, which is much appreciated.I assume you want me to follow the time-honoured custom of giving a Presidential address...

Jan 1, 1909

Stope back conditions in the cut-and-fill stopes at New Broken Hill Consolidated Limited often deteriorate to such an extent that, because conventional rockbolts are not able to maintain safe working conditions, square-set timber is installed. An attempt to eliminate this costly procedure has involved the use of long grouted rockbolts using high tensile prestressing wire. These bolts were developed in conjunction with the prestressing engineers of BBR (Aust.). This form of support has improved the back conditions, maintained safe working conditions, and delayed the introduction of timber in a number of stopes.Production from these stopes has been maintained at its previous level (at a rate approximately double that of a comparable timber stope).

Jan 1, 1974

Two structurally and mineralogically distinct sulphiderich veins cross-cutting the disseminated sulphides of the Nairne Pyrite Member appear to be products of local remobilization of sulphides under fracture-induced free energy gradients during regional metamorphism and tectonic deformation.The contrasting mineralogy of the two vein types may have arisen as a result of differences in the structural orientation of the veins and!or the relative ages of the veins.

Jan 1, 1969

By Thompson D. R, Milton R, Perry K. M A

From the Department for Research in Industrial Medicine (Medical Research Council), The London Hospital; and the De Havilland Aircraft Company:M.R.C. INVESTIGATIONS IN 1936In 1936 the Industrial Pulmonary Disease Committee of the Medical Research Council investigated both clinically and radiologically a group of fifty workers who had been exposed for a number of years to the inhalation of alumina in the reduction factory of the British Aluminium Company. The results are shown in Table 1.They also considered the sickness records of all the workers (Hill, 1936), as compared with those in other parts of the factory (Table 2).

Jan 1, 1945

By Matters C. W

THE following paper embodies the present practice and the results of past experience in the survey departments of two of the leading Broken Hill mines, the Central (Sulphide Corporation Ltd.) and the Broken Hill South S. M. Co. N. L.The authors intend to limit the scope of this paper to a consideration of office methods, as much has recently appeared in technical literature concerning field work, both surface and underground. Special reference may here be made to a valuable paper on 'Mine Surveying' by H W Gartrell, in Vol XIII of Transactions, in which the author gives considerable attention to field work. Moreover, much of the office work described in current literature is American, and sometimes not suited to local conditions, being ·often exceedingly elaborate and demanding a large staff of assistants. It is believed that the methods of recording information described in this paper are sufficiently simple and flexible to be adapted to most Australian mines. Brief acknowledgement must be made to the work done by Americans, who have raised mine surveying to the position of a separate profession, instead of being merely an unimportant branch of land surveying.

Jan 1, 1912

The ore is very 'refractory. It consists essentially of arsenical pyrites, iron pyrites, zinc blende, galena, antimony as sulphide and probably, in combination with galena, as Jamesonite, magnesium, and aluminium silicates with quartz. Some of the oxidized ore, of which there is very little, has a very interesting composition. A specimen shown to me by the ,general.manager, Mr. F. B. Stephens, consisted of hydrated arseniate of iron, orpiment, pyromorphite, lead oxide, with magnesium silicates and quartz. The ore found in the mine with a composition similar to this specimen was valued for gold contents at 60 oz. per ton. This ore is found as a small leader, which runs parallel to the main ore body, at intervals cutting through it.The ore is conveyed from the mine to the reduction works by means of a double road tram line. The mine is situated about rooo feet above the plant on a hill. The grade is so great (about I in 2) that the loaded trucks coming down are able to pullthe empty ones up, thus obviating the necessity of motive power for haulage. All that is necessary is two large grooved pulleys, fixed at the summit of the hilI, and provided with a rope-break for steadying the speed of the trucks down the hilI.

Jan 1, 1903

THE Talisman mine is situated on the Waitawheta (pronounced Wytaffetta) river just above its junction with the Chinemuri (pronounced Chinnemurre) river near Karangahake, NZ. The explored reef-bearing portion of the claim includes the angleformed by the junction of the rivers and extends southwards for slightly over a mile (See Plate V.). The country is mountainous both rivers flowing through precipitous gorges.The trig. station on Karangahake mountain is almost directly above the workings on the Bonanza section and is 1680 ft. above river level, the adit from the gorge giving 1200 ft. of backs measured vertically. The officers of the N.Z. Geological Survey are engaged in a detailed survey of the Waihi district and the rocks of Karangahake are under examination. The rocks of the district are andesites and dacites much altered and silicified. One of these exhibits a columnar structure in the mass in the Waitawheta gorge near the surface workings on Taukani hill, also on the southern bank...

Jan 1, 1912

By R H. Sillitoe

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Geological concepts are employed routinely in porphyry copper exploration at the area selection, prospect appraisal and deposit definition stages. Regional, district-scale, deposit-scale and laboratory-based concepts can all play a role, with the resulting porphyry copper models providing templates for the integration of geochemical and geophysical responses and interpretations. Of the 19 concepts and parameters selected for brief discussion, those relating to subdivision of porphyry intrusions, understanding of diverse and commonly complex alteration-mineralisation patterns and lithocap characterisation are undoubtedly the most influential in exploration. Several of them are of particular importance because of their role in promoting grade development. Additional belt-, district- and deposit-scale features are currently little used but hold promise, whereas others have less practical value but help in underpinning the evolving porphyry copper genetic model.CITATION:Sillitoe, R H, 2015. Recent advances in porphyry copper geology and their exploration utility , in Proceedings PACRIM 2015 Congress, pp 35–44 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015